1. Field of the Invention
This invention relates to a process for continuously and stably producing tows of carbon filaments having a high tenacity and Young's modulus and reduced fuzzing from polyacrylonitrile fibers as a raw material.
2. Description of the Prior Art
Many techniques, including those disclosed in Japanese Patent No. 304,892 and U.S. Pat. No. 3,285,696, have heretofore been suggested for producing carbon fibers from polyacrylonitrile fibers as a raw material. It is generally known that, in these techniques, the fibers are preoxidized in an oxidizing atmosphere at 200.degree. to 300.degree. C prior to carbonization. It is also known from U.S. Pat. No. 3,412,062, for example, that the application of tension to the fibers in the preoxidation step is effective to obtain carbon fibers having high tenacity and Young's modulus. These prior art techniques, however, fail to continuously produce carbon fibers of good quality in regard to tenacity, elasticity and filament breakage.